Constant-tension winch

ABSTRACT

A winch drum is coupled to an electric motor through a gear train, one section of which constitutes a cable drumline tension sensitive mechanism capable of changing position responsive to changes in cable drumline tension. An automatic tension control mechanism is coupled to the cable drumline tension sensitive mechanism for activation thereby to control the operation of the electric motor so as to maintain cable drumline tension between predetermined limits.

llnite States atent [56] References Cited UNlTED STATES PATENTS 2/1925 Johnson [72] Inventors Larry L.Dargitz;

Arthur J. Muhlbeier, both of Skagit, Wash. 804,522

Appl. No. Filed 1,527,555 254/172 2,966,221 12/1960 Kinney......................... 254/1738 [22] Mar. 5,1969 [45] Patented Sept. 28, 1971 Primary ExaminerEvon C. Blunk Assistant ExaminerAlfred N. Goodman Attorneys-Robert C. Smith and Plante, Hartz, Smith &

Thompson ABSTRACT: A winch drum is coupled to an electric motor through a gear train, one section of which constitutes a cable drumline tension sensitive mechanism capable of changing position responsive to changes in cable drumline tensionl An automatic tension control mechanism is coupled to the cable drumline tension sensitive mechanism for activation thereby to control the operation of the electric motor so as to maintain cable drumline tension between predetermined limits.

38 14 mnmnn ll. /4 m wm 2 %2 .m N n u m i m m m mm was o m on m m m 5 m m m m N U a r m m m m RM Twr m mh S TD "W M3 m 8 S, m m e T .l a a c mm a om s mm M 4 H NW N H w MU PATENTED SEP28 |97| SHEET 2 UF 2 INVENTORS LARRY LDARGETZ w HUR J. MUHLBEIER J BY ATTORNEYS CONSTANT-TENSION WINCl-ll The present invention provides mechanism for automatically controlling the line tension of a cable drum without employing unduly complicated and expensive tension control and sensing systems. The invention is particularly suited for use with mooring winches but has applicability to any winch system requiring automatic line tension control. The cablewinding power source and the cable drum of the winch are connected through a drive train which includes a cable drumline tension-sensitive mechanism capable of changing position responsive to changes in cable drumline tension. A tension control mechanism is coupled between the cable drumline tension-sensitive mechanism and the power source to operate the power source responsive to positional changes in the cable drumline tension-sensitive mechanism.

FIG. 1 of the drawings is a perspective view of a preferred winch construction;

FIG. 2 is a side elevation view of the winch drive train; and

FIG. 3 is a vertical cross section taken view the a preferred FIG. 2.

The preferred embodiment depicted comprises a winch drum l suitably mounted on drum shaft 12, a reversible drive power source 14 having a rotary power output shaft 116, a drive train 18 interconnecting shafts 12 and 16, automatic tension control switch block 20, and a tension selector 22. Although not shown, the aforementioned components would be operably mounted by a suitable framework as well known in the art.

The interconnecting drive train 18 comprises a bull gear 24 secured to drum shaft 12, a drive pinion 26 secured to shaft 16, and a walking rotary motion transfer mechanism 28. This latter mechanism comprises a pair of sideplates 30 and 32, each journal mounted to shaft 16 on opposite sides of pinion 26 and connected to the other by cross plate 34, a first idler gear 36 journal mounted to the plates 30 and 32 by shaft 38 and meshed with pinion 26, an idler pinion 40 secured to shaft 38, and a second idler gear 42 journal mounted by shaft 16 and meshed with idler pinion 40 and bull gear 24.

Since pinion 26 and idler gear 42 are coaxially mounted and idler pinion 40 and idler gear 36 are coaxially mounted, the two pinions are identical and the two idler gears are identical. Furthermore, this structural identity is necessary to the walking function of mechanism 28.

Tension control switch block 20 comprises at least two stationary electrical switch contacts 44 and 46 with their contact terminals positioned on the periphery of an arc, and a rotatable contact arm 48 having a control end arranged to engage the terminals of contacts 44 and 46. Contact arm 48 is secured to a rotatable rod 50, the opposite end of which mounts a lever arm 52 which is pivotally connected to cross plate 34 by connecting rod 54.

Tension selector 22 comprises an actuating lever arm 56 rotatably engaged with rod 50, a selector plate 58, and a locking pin 60 adapted to engage notches in the side of plate 58 to hold a desired position of arm 56 relative to plate 58.

A spring tension mechanism 62 is mounted to act on mechanism 28 against tension selector 22. The spring tension mechanism comprises a stationary housing 64, a spring plunger rod 66 secured to cross rod 68 that is pivotally mounted in plates 30 and 32, and a compression spring 70 contained between rod 66 and housing 64 by retainer washers 72 and 74. A hydraulic dampener 76 is connected between plate 30 and a stationary mounting to act against mechanism 62.

Power source 14 preferably comprises a reversible electric motor electrically coupled to switch block 20 such that completion of an electrical circuit through elements 44 and 48 will actuate the motor to wind cable onto drum l0, and such that completion of an electrical circuit through elements 46 and 48 will actuate the motor to pay cable from drum 1%). Power source 14 also comprises an output shaft brake 14a electrically coupled to switch block 20 such that completion of an electrical circuit through switch block 20 will release shaft brake 14a, and such that breaking the circuit through switch block 20 will actuate the shaft brake 14a to prevent rotation of shaft 16 and drive pinion 26.

The tension in cable 1 will tend to rotate drum 1'!) and bull gear 24 in the direction of arrows 2 and! 3, to rotate idler gear 42 in the direction of arrow 4, and to rotate idler gear 36 in the direction of arrow 5. Since output shaft 16 and pinion 26 are braked, rotation of bull gear 24 can only drive freewheeling idler gear 42. Consequently, rotation of idler gear 42 will tend to cause mechanism 28 to pivot around shaft 116 in the direction of arrow 6 with idler pinion 40 and idler gear 36 tending to walk around their respective meshed gears 42 and 26.

If the system is in equilibrium, spring; 70 will resist the tendency of mechanism 28 to pivot. If the tension in cable 1 exceeds the tension setting of selector 22,. however, mechanism 28 will pivot and, through link 54, lever 52 and rod 50, swing contact arm 48 into engagement with contact 46, thereby activating motor 14 and releasing brake 14a to pay cable from drum 10. When enough cable has been paid from drum to again equalize the load forces, spring 70) will decompress and cause mechanism 28 to pivot in the opposite direction until contact 48 is shifted out of engagement with contact 46 and brake 14a is actuated to halt rotation of shaft 16.

If tension in cable 1 decreases below the tension setting of selector 20, spring 70 will decompress and pivot mechanism 28 until contact arm 48 shifts into engagement with contact 44, thereby activating motor 114 and releasing brake 14a to wind cable onto drum it). As the tension in cable 1 increases, spring 70 will compress because of the planetary effect through gears 42 and 26. When spring 70 has compressed to the tension set by selector 22 and mechanism 28 has pivoted accordingly, contact arm 48 will have shifted out of engagement with contact 44 and brake 14a activated to halt rotation ofshaft 16.

Any spring-hunting tendency will be dampened by dampener 76.

It is believed that the invention will have been clearly understood from the foregoing detailed description of our nowpreferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly our intention that no limitations be implied and that the hereto-annexed claims be given the broadest interpretation to which the employed language fairly admits.

Iclaim:

l. A constant-tension winch assembly which comprises a cable drum;

a power source;

automatic tension control means coupled to effect activation of said power source to maintain line tension on said cable drum between predetermined limits;

and a drive train interconnecting said cable drum and said power source, said drive train including a cable drumline tension-sensitive mechanism coupled to activate said tension control means responsive to changes in cable drum line tension, and a gear train including a first gear rotatable by said power source and a second gear rotatable with said cable drum;

said cable drumlike tension-sensitive mechanism including means interconnecting said first and second gears, a section of said interconnecting means being movable with respect to said first and second gears and responsive to changes in cable drumline tension, said tension control means being coupled to said section.

2. A constant-tension winch assembly which comprises a cable drum;

a power source;

automatic tension control means coupled to effect activation of said power source to maintain line tension on said cable drum between predetermined limits;

and a drive train interconnecting said cable drum and said power source, said drive train including a cable drumline tension-sensitive mechanism coupled to activate said tension control means responsive to changes in cable drumline tension, and a gear train including a first gear rotatable by said power source and a second gear rotatable with said cable drum;

said cable drumline tension-sensitive mechanism including a first idler gear meshed with said first gear, a second idler gear meshed with said second gear and a third gear meshed with said second idler gear and freely rotatable relative to said first gear, and means coaxially mounting said second idler gear and said third gear for revolution about their respectively meshed gears responsive to relative rotation between said first and third gears, said tension control means being coupled to said mounting means.

3. The assembly of claim 2 wherein said cable drumline tension-sensitive mechanism includes resilient means acting against cable drumline tension; and selector means coupled to said resilient means to preset said tension control means to maintain a desired cable drumline tension.

4. A constant-tension winch assembly which comprises a cable drum; an electric motor having a rotary output shaft and an electrically actuatable shaft brake; a first gear rotatable by said output shaft, a second gear rotatable with said cable drum, a third gear joumaled on said output shaft and meshed with said second gear; a cable drumline tension-sensitive mechanism comprising gear mounting means pivotally mounted by said output shaft, first and second idler gears coaxially mounted by said gear mounting means and meshed with said first and third gears respectively such that said idler gears are operable to transfer rotary motion between said first and third gears, and to revolve around said first and third gears responsive to relative rotation between said first and third gears, and resilient means coupled to said gear-mounting means and acting against cable drumline tension; and automatic tension control means electrically coupled to effect activation of said motor and shaft brake and coupled to said cable drumline tension-sensitive mechanism to activate said motor and release said brake responsive to position changes of said cable drumline tension-sensitive mechanism caused by changes in cable drumline tension.

5. The assembly of claim 4 including selector means coupled to said resilient means to preset said tension control means to maintain a desired cable drumline tension. 

1. A constant-tension winch assembly which comprises a cable drum; a power source; automatic tension control means coupled to effect activation of said power source to maintain line tension on said cable drum between predetermined limits; and a drive train interconnecting said cable drum and said power source, said drive train including a cable drumline tensionsensitive mechanism coupled to activate said tension control means responsive to changes in caBle drumline tension, and a gear train including a first gear rotatable by said power source and a second gear rotatable with said cable drum; said cable drum line tension-sensitive mechanism including means interconnecting said first and second gears, a section of said interconnecting means being movable with respect to said first and second gears and responsive to changes in cable drumline tension, said tension control means being coupled to said section.
 2. A constant-tension winch assembly which comprises a cable drum; a power source; automatic tension control means coupled to effect activation of said power source to maintain line tension on said cable drum between predetermined limits; and a drive train interconnecting said cable drum and said power source, said drive train including a cable drumline tension-sensitive mechanism coupled to activate said tension control means responsive to changes in cable drumline tension, and a gear train including a first gear rotatable by said power source and a second gear rotatable with said cable drum; said cable drumline tension-sensitive mechanism including a first idler gear meshed with said first gear, a second idler gear meshed with said second gear and a third gear meshed with said second idler gear and freely rotatable relative to said first gear, and means coaxially mounting said second idler gear and said third gear for revolution about their respectively meshed gears responsive to relative rotation between said first and third gears, said tension control means being coupled to said mounting means.
 3. The assembly of claim 2 wherein said cable drumline tension-sensitive mechanism includes resilient means acting against cable drumline tension; and selector means coupled to said resilient means to preset said tension control means to maintain a desired cable drumline tension.
 4. A constant-tension winch assembly which comprises a cable drum; an electric motor having a rotary output shaft and an electrically actuatable shaft brake; a first gear rotatable by said output shaft, a second gear rotatable with said cable drum, a third gear journaled on said output shaft and meshed with said second gear; a cable drumline tension-sensitive mechanism comprising gear mounting means pivotally mounted by said output shaft, first and second idler gears coaxially mounted by said gear mounting means and meshed with said first and third gears respectively such that said idler gears are operable to transfer rotary motion between said first and third gears, and to revolve around said first and third gears responsive to relative rotation between said first and third gears, and resilient means coupled to said gear-mounting means and acting against cable drumline tension; and automatic tension control means electrically coupled to effect activation of said motor and shaft brake and coupled to said cable drumline tension-sensitive mechanism to activate said motor and release said brake responsive to position changes of said cable drumline tension-sensitive mechanism caused by changes in cable drumline tension.
 5. The assembly of claim 4 including selector means coupled to said resilient means to preset said tension control means to maintain a desired cable drumline tension. 